Is source elevation an auditory distance cue? A preliminary study.

The aim of this work was to evaluate whether the angular elevation of a sound source could generate auditory cues which improve the auditory distance perception in a similar way to that previously reported by visual modality. For this purpose, we compared ADP curves obtained with sources located both at the listeners' ears and at ground level. Our hypothesis was that the participants can interpret the relation between elevation and distance of ground-level sources (which are linked geometrically) so we expected them to perceive their distances more accurately than those at ear level. However, the responses obtained with sources located at ground level were almost identical to those obtained at the height of the listeners' ears, showing that, under the conditions of our experiment, auditory elevation cues do not influence auditory distance perception.

Effects of Cycloleucine in the Nucleus Accumbens Septi on the Elevated plus Maze Test in Rats.

INTRODUCTION: In recent years, an important number of studies have emphasized the psychopharmacological actions of cycloleucine (1-aminocyclopentanecarboxylic acid) acting on the NR1 subunit (glycine allosteric site) of NMDA (N-methyl-D-aspartic acid) receptor. We studied the effects of its injection in an anxiety test. METHODS: The elevated plus maze test was used. Male rats bilaterally cannulated into the nucleus accumbens septi (NAS) were employed. Rats were divided into 5 groups that received either 1 µL injections of saline or cycloleucine (0.5, 1, 2, or 4 µg) 15 min before testing. RESULTS: Time spent in the open arm was significantly increased by cycloleucine treatment with all doses (1 and 2 µg, p < 0.05; 0.5 and 4 µg, p < 0.01), like number of extreme arrivals (0.5 and 1 µg, p < 0.05; 2 µg, p < 0.01; and 4 µg, p < 0.001). Open arm entries were increased by the highest dose only (4 µg, p < 0.01). DISCUSSION/CONCLUSION: Present results show no difference between all doses in the time spent in the open arm, suggesting an indirect, noncompetitive action of the drug. The increase in extreme arrivals and open arm entries suggests a dose influence in these parameters. We conclude that cycloleucine influence on the NMDA receptors within NAS leads to anxiolytic-like effects and behavioral disinhibition, which once more confirms the involvement of NAS in anxiety processing.

A new rabbit species (Sylvilagus, Mammalia: Leporidae) from the lowlands of Venezuela

A new species of Venezuelan rabbit of the genus Sylvilagus from Fundo Millano (08 degrees 46'N and 69 degrees 56'W) and Chorrosco Bajo (08 degrees 05'N and 69 degrees 18'W), between 190 and 120 masl, state of Barinas, is described based on: 1. Body and skull measurements. 2. Coloration patterns of the pelage. 3. Arrangement and length of the color hair bands of dorsal, lateral, ventral nuchal, and gular patches. Body and cranial measurements, and some color patterns of the new species, Sylvilagus varynaensis, were compared with those of the closest relative groups such as S. brasiliensis (from Venezuela and Brazil), S. b. meridensis from the Venezuelan paramos, and three of the most representative groups of S. floridanus (S. f. continentis, S. f. orinoci, and S. f. valenciae). Most of the values recorded for these parameters were significantly higher for the new species (P < 0.005; Student "t" test). Cluster and principal components analysis of the data recorded for cranial characteristics indicated that S. varynaensis is the largest and darkest of the known Venezuelan rabbits, with a broader elongated skull and a different arrangement of the color hair bands.